Calculate the electric field strength required to just support an oil drop of mass
10 -2 kg and having a charge 3.2 x 10 -19 C.

Explanation:

As we know that the oil drop experiment tells us the balancing the gravitational force by electrostatic force.

So ,

Electrostatic force = Gravitational force

qE=mg

Here , q is charge , E is electric field , m is mass and g is gravity.

so,

Insert values from question,

or

This is the required value of electric field.

they should be similar or the same